Prior Art
In the ore refining, mineral processing and certain other chemical industries, it is well known that some raw materials are difficult to reduce from their natural state to their constituent elements. One long-known method for reducing these materials is to introduce them into a high-temperature environment for a requisite period of time. To achieve the requisite high temperatures necessary to reduce complex materials, electric current may be converted into high temperature effluents which, by virtue of their high temperature and enthalpy, interact with the raw material, causing a higher rate of reaction than would take place at a lower temperature. Consequently, in the electrometallurgical arts, there are many known electric arc furnaces, including the use of a plasma, to refine materials.
In U.S. Pat. No. 4,394,162, Tylko discloses a plasma reactor wherein an electrical arc discharge is produced between stationary electrode segments or structures and is then pulsated to produce acoustic shock waves or discontinuities which produce a region of plasma in the interelectrode space. The arc discharge is caused to orbit or circulate around the cathode by electromagnetic means.
Another patent which discloses the use of a magnetic field to rotate the plasma is U.S. Pat. No. 3,851,136 (to Venus), but Venus requires stationary, axially spaced electrodes located remote from the magnetic field.
Despite the advances in the metallurgical arts represented by the above-cited prior art patents, many problems remain. For example, the establishment and maintenance of a stable plasma to effect longer retention of the material to be refined, heretofore has been unachieved. Undue electrode contamination and the shortness of electrode life remain a source of inefficiency in plasma reaction chambers, and the short life and damage of furnace or reaction chamber walls or linings due to the discharge arc and high temperatures is yet a severe problem.